A computer-based eye movement contingent display control system has been developed for the investigation of perceptual processes during fixation in reading. The proposed research involves using this system, together with the analysis of eye movement data, to investigate a number of questions about perceptual processes during reading: What visual information is obtained from different retinal regions during fixation? What is the sequence in which information is attended during a fixation? How are the perceptual processes influenced by language constraints in the text? How do they change as different reading strategies are adopted? What is the nature of eye movement control during reading? What information is carried across from one fixation to the next?